Transcript GIT.L3-NEOPLASMS OF THE STOMACH.ppt

Benign
Epithelial
Mesenchymal
Malignant
Epithelial
Mesenchymal
Lymphoma
Carcinoid
Tumors of the Stomach
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Tumors arising from the mucosa predominate over
mesenchymal tumors.
These are classified into polyps and carcinoma.
The term “polyp” is applied to any nodule or mass
that projects above the level of surrounding
mucosa
The use of the term “polyp” in GI tract is generally
restricted to mass lesions arising in the mucosa.
NEOPLASMS OF THE STOMACH
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Benign
 Epithelial
○ hyperplastic polyps
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Fundic gland polyps
○ Adenomatous polyps.
 Mesenchymal
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Malignant
 Epithelial
 Mesenchymal
 Lymphoma
 Carcinoid
Benign Neoplasms of Stomach
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Mucosal polyps
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Epithelial polyps are rare. (0.4%)
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Types:
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1] hyperplastic polyps; (80% to 85%
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2] Fundic gland polyps (∼10%)
3] Adenomatous polyps (∼5%)
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Appear as sessile or small pedunculated lesions, often multiple
that can be removed endoscopically.
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All three types arise in patient with chronic gastritis.
Large polyps are very rare.
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- The risk of carcinoma is moderate in adenomatous
polyp, slight in hyperplastic polyp, and nil in fundic
gland polyps.
Adenomatous polyp of the stomach. Note the large size of
the polyp and its lobulated configuration.
A small ulceration ( arrow) can be identified on its surface.
Malignant neoplasm of stomach
-
Carcinoma – 90-95%
Lymphoma – 4%
Carcinoids – 3%
Malignant spindle cell – 2%
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Gastric carcinoma is the second leading
cause of cancer-related deaths in the
world, with a widely varying geographic
incidence.
Malignant neoplasm of stomach
1.
Gastric adenocarcinoma
Epidemiology
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The incidence of gastric carcinoma is five to ten times
higher in Japan than in the United States. It is also high
in China and Chile.
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There are two patterns Intestinal
.
type and Diffuse type
Intestinal type
occur on top of ch.
Gastritis and intestinal
metaplasia and
common in high risk
population after age
50 with 2:1 male
predominance
Diffuse type
arise de novo in
younger age group
with with female
predominance
In the United States, the incidence of Intestinal type had declined since 1950
Gastric adenocarcinoma
Risk factors for Gastric Carcinoma
 Intestinal type adenocarcinoma
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Diet
 Nitrites
 Smoked foods
 Excessive salt
 Decreased intake of fresh vegetables and fruits
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Ch. Gastritis and intestinal metaplasia
 Infection by H. pylori
 Pernicious anemia
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Altered anatomy
Diffuse Carcinoma
Undefined, E- cadherine (50%), FGFR2 (33%)
Amplification of HER-2/NEU and
increased expression of β-catenin are
present in 20% to 30% of cases and
are absent in diffuse carcinoma
Malignant neoplasm of stomach
Gastric Carcinoma
 Precancerous lesions ( intestinal type)
1. Chronic atrophic gastritis associated
with pernicious anemia.
2. Chronic atrophic gastritis associated
with helicobacter pylori infection.
3. Those with adenomatous and hyperplastic
polyps.
4. Following subtotal gastrectomy.
Malignant neoplasm of stomach
Gastric carcinoma
Site:
- pylorus and antrum – 50-60%
- cardia – 25%
- body and fundus 15 -25%
lesser curvature 40%
Greater curvature 12%
a favored location is the lesser curvature of the antropyloric region
Malignant neoplasm of stomach
Gastric carcinoma
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Divided into:
1. Early gastric cancer (lesion limited to mucosa and submucosa)
– appears as a small, flat mucosal thickening that may have a minimal
polypoid and ulcerative component.
2. Late gastric cancer
– defined as a gastric carcinoma that has invaded the muscle wall.
It may present in various ways:
- As a fungating mass that protrudes into the lumen.
- As a diffusely infiltrating lesion that causes thickening and
contraction of the stomach wall with relatively little mucosal
involvement (linitis plastica, or leather-bottle stomach).
- As a malignant ulcer (excavated) with raised, everted edges.
Malignant neoplasm of stomach
Malignant neoplasm of stomach
Any gastric ulcer that does not heal as expected
should be biopsied to rule out carcinoma.
Gastric carcinoma
Intestinal type
The diffuse variant of gastric carcinoma
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Arise de novo from native gastric-type mucous cells that
generally do not form glands but rather permeate the
mucosa and wall as scattered individual “signet-ring”
cells or small clusters in an infiltrative growth pattern.
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There is no association with chronic gastritis
Poorly differentiated
It occurs at early ages with female predominance.
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Risk factors undefined
 Rare inherited mutation of E-cadherin leading to
autosomal dominant inheritance.
 Mutations in FGFR2, a member of the fibroblast growth factor
receptor family, and increased expression of metalloproteinases
are present in about one-third of cases, but are absent in
intestinal-type carcinomas.
Gastric carcinoma
Intestinal type
Diffuse variant
Malignant neoplasm of stomach
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Spread of Gastric carcinoma
Direct:
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Lymphatic metastasis
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Invades through the muscle wall into the
omental fat.
Spread of tumor cells in the peritoneal fluid.
Spread to the ovary (Krukenberg’s tumor) and
rectovesical pouch.
to lymph nodes around the stomach
Left supraclavicular node (Virchow’s node)
Lymph node metastases are present in about
50% of cases at the time of diagnosis
Blood stream spread to the liver and lung
Malignant neoplasm of stomach
Clinical Features of Gastric carcinoma
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Early gastric cancer:
 asymptomatic
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Late gastric cancer:
 Resembling chronic peptic ulcer
 Anorexia, anemias, weight loss, hematemesis and melena.
 Tumors near the pylorus may cause gastric outlet obstruction.
Malignant neoplasm of stomach
Prognosis of Gastric carcinoma
 The prognosis depends on the depth of invasion of the
neoplasm.
Early cancer
- 85% - 5 years survival
Muscle wall invasion – 30% - 5 years survival
Full thickness invasion and lymph node – 5% - 5 year
survival
 Histologic features and differentiation are of little prognostic
importance.
Malignant neoplasm of stomach
2.
Malignant lymphoma
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Two common types occur:
a. Low-grade malignant lymphoma arising in
mucosa- associated lymphoid tissue (MALT
lymphoma).
b. High-grade aggressive B cell lymphomas, most
commonly B immunoblastic lymphoma.
Present as polypoid masses, ulcers, thickened
fold.
MALT lymphoma restricted to can be cured by
surgical resection ( more likely to be associated
with H. pylori)
High grade lymphomas respond to chemotherapy,
and
have a 5 year survival rate of about 60%.
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Malignant neoplasm of stomach
3.
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Malignant gastric stromal neoplasms
Commonest mesenchymal neoplasm (2% of gastric
malignancies)
Arise from undifferentiated mesenchymal cells in the
gastric wall with ulceration.
Present as large masses that originate in and involve the
wall with ulceration.
Composed of spindle cells that show varying cellularity,
pleomorphism and mitotic activity
with smooth muscle or neural
differentiation.
Treatment: Surgical resection
over 50% survive 5 years.
Malignant neoplasm of stomach
4.
Carcinoid tumors
- extremely rare.
- give metastasis in 30% of cases.
Summary of Gastric Tumors
More than 90% of gastric tumors are carcinomas;
lymphomas, carcinoids and stromal tumors are relatively
infrequent.
 The two main types of gastric adenocarcinomas are the
intestinal and diffuse types; macroscopic patterns of both
types may be exophytic, flat or depressed, or excavating.
 Intestinal type of adenocarcinoma is associated with
chronic gastritis caused by H. pylori infection, with gastric
atrophy and intestinal metaplasia; composed of malignant
cells forming intestinal glands.
 Diffuse type of adenocarcinoma is not associated with H.
pylori infection; composed of gastric type of mucous cells
(signet ring cells) that permeate the mucosa without
forming glands.
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